There are angles whose measures add to 180°. Their measures are m A = 67°, m B = (2x+20)°, and m C = x°. What is the measure of B?

A. 82°
B. 31°
C. 180°
D. 62°

1 answer

The sum of the measures of angles A, B, and C is equal to 180°. Therefore, we can write the equation:

m A + m B + m C = 180°

Substituting the given values, we have:

67° + (2x + 20)° + x° = 180°

Combining like terms, we get:

3x + 87° = 180°

Subtracting 87° from both sides, we have:

3x = 93°

Dividing both sides by 3, we find:

x = 31°

Now, we can substitute the value of x back into the expression for angle B:

m B = 2x + 20°

m B = 2(31°) + 20°

m B = 62° + 20°

m B = 82°

Therefore, the measure of angle B is 82°.
The answer is A. 82°.